Irish history is apt to be obscured by a cloud of semantics so, at the outset, Northern Ireland is defined as the historic nine-county province of Ulster: Antrim, Armagh, Cavan, Donegal, Down, Fermanagh, Londonderry, Monaghan and Tyrone. This is neither geographically nor economically a homogeneous region but the outcome of an amalgam of Gaelic-Irish and Anglo-Irish lordships and subjected to substantial English and Scottish settlement from the late sixteenth century. Since 1922 six of the nine counties have formed a smaller political unit – also called, confusingly, Ulster or Northern Ireland – and as with the larger area this too lacks an economic unity.

By virtue of physical geography and climate there exist many variations in landscape and settlement patterns in Ulster. These range from extensive areas of lowland in the valleys of the Lagan, Bann and Foyle, the Lough Neagh basin, Counties Fermanagh and Cavan, and the eastern lowlands of Antrim and north Down to the mountain masses of the Sperrins and Mournes, the rocky uplands of north-west Donegal and north Antrim and the chain of drumlins stretching from south Donegal to the Ards peninsula. Rainfall and temperature made Ulster natural pasture country but local needs and, in the later eighteenth and early nineteenth centuries, the demands of distant markets, created an extensive mosaic of small tillage farms producing mainly potatoes and oats, the former for subsistence and the latter for sale.

Is there then any sort of unity that justifies treating the nine-county Ulster as a single region in the pre-factory age, a period defined for present purposes as roughly 1700–1850! Three unifying themes can be identified.